The goal of the overall project is to examine the impact of diabetes on the coupling of bone formation following an episode of alveolar bone resorption to better understand how diabetes can aggravate periodontal disease progression. We propose to investigate two mechanisms through which diabetes could cause uncoupling that were not in the original application, the impact of diabetes-enhanced inflammation on proliferation and differentiation of mesenchymal/osteoblastic cells lining alveolar bone. The competitive revision also includes the addition of a new animal model to address a potentially important aspect of the disease process that was not readily addressed in the original animal model. By using an A. actinomycetemcomitans model of periodontal bone loss we will be able to assess the impact of diabetes on the pathogenic microbial component. By fluorescent in-situ hybridization we will quantify A. actinomycetemcomitans colonization and/or invasion. The results may provide exciting new findings and important insight into mechanism by which diabetes affects periodontal bone loss. These revisions incorporate two important objectives listed by the NIDCR, a) the scope of the proposal is significantly expanded within the context of the original goals and b) a new investigator with a different background (microbiology) has been brought into the study as a co-investigator, Dr. Daniel Fine. Dr. Fine's involvement will facilitate the use of the new model. The revisions will accelerate the research objectives by the purchase of new equipment and software to enhance capture and analysis of fluorescent images, and create two new positions. A post-doctoral fellow will be hired to carry out the expanded scope of the research along with a part-time research assistant (75%). PUBLIC HEALTH RELEVANCE: The goal of the proposed studies is to investigate in greater depth a mechanism for diabetes-enhanced periodontal bone loss, uncoupling of bone formation and resorption by diabetes. We will use a new animal model in which bone loss is initiated by the introduction of A. actinomycetemcomitans. This model has the advantage of a better defined microbial component compared to the original animal model. In addition, we will investigate additional mechanisms by which this may occur, the impact of diabetes-enhanced inflammation on proliferation and differentiation of alveolar mesenchymal/osteoblastic cells in vivo.